• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3534-3553
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• 2021

The low cost of Bluetooth technology has led to its wide usage in indoor positioning. However, some inherent shortcomings of Bluetooth technology have limited its further development in indoor positioning, such as the unstable positioning state caused by the fluctuation of Received Signal Strength Indicator (RSSI) and the low transmission frequency accompanied by a poor real-time performance in positioning and tracking moving targets. To address these problems, an indoor fusion positioning algorithm of Bluetooth technology and pedestrian dead reckoning (PDR) based on a particle filter with dynamic adjustment of weights calculation strategy (BPDW) will be proposed. First, an orderly statistical filter (OSF) sorts the RSSI values of a period and then eliminates outliers to obtain relatively stable RSSI values. Next, the Group-based Trilateration algorithm (GTP) enhances positioning accuracy. Finally, the particle filter algorithm with dynamic adjustment of weight calculation strategy fuses the results of Bluetooth positing and PDR to improve the performance of positioning moving targets. To evaluate the performance of BPDW, we compared BPDW with other representative indoor positioning algorithms, including fingerprint positioning, trilateral positioning (TP), multilateral positioning (MP), Kalman filter, and strong tracking filter. The results showed that BPDW has the best positioning performance on static and moving targets in simulation and actual scenes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.2976-2990
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• 2022

The adaptive adjustment of reference or weight vectors in decomposition-based methods has been a hot research topic in the evolutionary community over the past few years. Although various methods have been proposed regarding this issue, most of them aim to diversify solutions in the objective space to cover the true Pareto fronts as much as possible. Different from them, this paper proposes a knee point-based reference vector adaptive adjustment strategy to concurrently balance the convergence and diversity. To be specific, the knee point-based reference vector adaptive adjustment strategy firstly utilizes knee points to construct the adaptive reference vectors. After that, a new fitness function is defined mathematically. Then, this paper further designs a many-objective evolutionary algorithm with knee point-based reference vector adaptive adjustment strategy, where the mating operation and environmental selection are designed accordingly. The proposed method is extensively tested on the WFG test suite with 8, 10 and 12 objectives and MPDMP with state-of-the-art optimizers. Extensive experimental results demonstrate the superiority of the proposed method over state-of-the-art optimizers and the practicability of the proposed method in tackling practical many-objective optimization problems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권8호
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• pp.2157-2169
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• 2023

In order to handle the problem that puncture patterns will change the position distribution of original information bits and frozen bits in polar codes, which affects performance of puncture polar codes further, a minimum row weight and polar spectrum based puncture polar codes construction algorithm (called PA-MRWP) is proposed in this paper. The algorithm calculates row weight of generator matrix and sorts the row weight in ascending order first. Next, the positions with the minimum row weight are selected as initial puncture positions. If the rows with the same row weight cannot all be punctured, polar spectrum based auxiliary puncture scheme is used. In sub-channels with the same row weight, rows corresponding to the polarized sub-channels with higher reliability are selected as puncture positions to construct puncture vector, and the reliability is calculated based on polar spectrum. It is actually a two-step selection strategy, the proposed minimum row weight puncture (MRWP) algorithm is used for primary selection and polar spectrum based auxiliary puncture is used for adjustment. Simulation results show that, compared with worst quality puncture (WQP) algorithm, the proposed PA-MRWP algorithm and Gaussian approximation-aided minimum row weight puncture (GA-MRWP) algorithm provide gains of about 0.46 dB and 0.29 dB at bit error rate (BER) of 10^-4, respectively when code length N=400, code rate R=1/2. In addition, the proposed puncture algorithms improve the BER performance significantly with respect to quasi-uniform puncture (QUP) algorithm.

• 한국학교보건학회지
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• 제14권1호
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• pp.115-130
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• 2001

Dieting behaviors prevail among most women and are highly increasing among female adolescents who don't have to lose weight. The dieting behaviors of normal or low weight groups are highly related to the negative impact of health risk behaviors. We need a strategy for intervening in the dieting behaviors of relevant groups. With this background, a study was conducted to examine the current situation of dieting behaviors and related factors in middle school girls, and to provide guidelines for the relevant dieting group. This survey was carried out by self-questionnaires passed out to 901 middle school girls from 3 middle schools in Seoul. Data were collected from April 10th, 2000 to April 17th, 2000 and 794 respondents' data were finally selected for analysis. The instruments of this study were Shin's scale for effects of mass-media, Birleson's depression self-rating scale translated by shim, Rosenberg's self-esteem scale, Smilkstein's Family APGAR score translated by Yoon, Kim's school-related adjustment scale. The credibility of instruments was 0.41~0.83 in the pilot study and 0.70~0.86 in the main study. The summary of results was as follows: 1. The general characteristics of respondents were analyzed. In comparison of grade and dieting behaviors, the subjects of the group perceived that their body image was obeser than their real body image and their ideal body image was slenderer than their current body image. A dieter's body image was seriously distorted. 2. The dieting behaviors were analyzed. The Subjects' BMI was within the normal to low range -- they didn't have to lose weight. But actually 47.3% of the respondents were dieters. Their main dieting methods were exercise(71.8%), computer games(64.9%) such as DDR and pump, and intake reduction(64.1%). Most dieters were using desirable methods such as exercise and intake control. But unhealthy methods such as saunax, smoking and harmful drug-use were also used by a few dieters. The main reason for dieting was attractiveness. The chief resources of dieting methods were mass-media(67.8%), friends(64.3%), and parents & relatives(35.1%). Only a few subjects obtained the information from health professionals. While they were trying to lose weight, 42.1% of the subjects experienced side effects such as dizziness(45.0%), apathy(20.5%), appetite loss(18.5%), amenorrhea and the irregularity of the menstrual cycle(16.6%). 3. The relationship between dieting behaviors and factors was analyzed. Dieting behaviors were significantly related to the experience of menarche, the experience of dating with heterosexuals, perceived body image, self-esteem, depression, family's relationship, school instruction-related adjustment, school life-related adjustment, and the effect of mass-media. After that, the multiple logistic regression was used. The analysis revealed that dating, perceived body image, the experience of menarche and the effect of mass media were significant factors. In conclusion, strategies for preventing irrelevant dieting behaviors are urgently required to enhance female adolescents' ability to choose the right information from countless others and to recognize their optimum body image.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.35-44
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• 2018

본 연구는 서비스 로봇 개발을 추진하기 이전 기획단계에서 개발 비용에 영향을 미치는 항목을 도출하고, 각 항목별 영향력의 크기와 우선순위를 도출하기 위한 연구이다. 특히 서비스 로봇은 적용 환경과 수행해야 할 임무에 따라 요구되는 기능, 부품이 달라지고 이에 따른 가격이 천차만별일 뿐만 아니라 소량생산이 대부분으로 비용 추정의 중요성이 강조된다. 이에 따라, 본 연구에서는 서비스 로봇 개발 및 기능을 추가하는 과정에서 특정 임무를 위해 추가되는 각종 센서, 매니퓰레이터, 통신모듈 등 개별적으로 비용에 영향을 미치는 요소를 기능 항목으로, 운용되는 환경이나 개발과정에서 충족해야 하는 방진, 방수, 내구성 테스트 등 개발 비용에 전체적으로 영향을 미치는 요소를 조정 항목으로 구분하고, 각 항목별 세부 기준을 도출하기 위한 FGI를 수행하였다. 또한 각 항목별 비용 가중치 결정을 위하여 국내 전문가 84명을 대상으로 델파이 조사를 시행하였다. 분석 결과, 기능 항목 6개(세부 기준 41개), 조정 항목 5개(세부 기준 17개)가 도출되었으며, 각 항목별로 비용 가중치와 순위를 제시하였다. 본 연구를 통해 서비스 로봇 개발 기획단계에서 개발비용을 추정하고, 기능을 선택할 수 있는 의사결정 요소로 활용 할 수 있다면, 기업이 서비스 로봇 개발의 전략적 도구로 활용할 수 있을 것이며 이를 통한 시장 진입과 확장에 도움이 될 것으로 예상된다.

• 한국항만경제학회지
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• 제33권3호
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• pp.139-154
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• 2017

국내외 항만간 경쟁이 심화됨에 따라 국내 신생 및 중소형 항만이 자체적으로 경쟁력을 확보하는데 한계가 있다. 이에 본 연구에서는 경인항을 중심으로 컨테이너 및 일반화물 물동량 5개변 60개월치의 데이터로 단기간 (12개월)의 물동량을 각각 예측하였고 중장기적으로는 어떠한 발전 방안이 필요한지 검토하였다. 첫 번째, 경인항 배후 물류단지와 연계하여 정밀기계, 홈네트워크시스템, LED, 기계공업 등의 품목을 대중국 항로로 유치하고, 두 번째, 초중량 화물 운송루트로 특화하고, 서해5도 연안섬 지역과 아라뱃길(서해5도수산물복합센터)을 연계함으로서 수산물 운반 및 여객선 준공영제를 통한 연안해운 활성화에 기여할 것으로 판단된다. 세 번째, 정부-지자체-항만의 유기적인 협력을 바탕으로 인센티브 등 선순환 지원제도가 필요하고, 마지막으로 수도권 항만의 통합운영을 통해 인근항만간 기능 조정 및 특화전략이 병행 추진되어야 할 것이다.

• Strategy21
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• 통권41호
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• pp.261-293
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• 2017

Nuclear power is a way of attaining an enormous amount of energy with relatively small amount of resources and after it has been introduced to the submarine since 1954, there are approximately 150 of nuclear powered submarine currently on a mission around the world. This is due to the maneuverability, mountability and covertness of nuclear submarines. However, there are other tasks, not only the high level of nuclear technology that are needed to be dealt with in order to construct nuclear powered submarine. The biggest task of all is to secure the enriched uranium. Accordingly, this research is about the way of enriching and securing the nuclear fuel that are used in the nuclear submarine with the characteristics, merits and demerits of the nuclear submarine. Due to the fact that the pressurized water reactor in South Korea is the reactor that was originally built for the development of nuclear powered submarine, many parts is designed to be suitable for the submarine propulsion. However, in order to apply this to submarine it is needed to consider additional requests such as the position of reactor, accident-coping system, radioactive covering, reactor output adjustment and ship's pitch and roll in order to apply this to submarine. Nuclear submarines have much higher speed based on the powerful propulsion in comparison with diesel-electric submarine and also have bigger loading area. Besides, there is no need to snorkel and they also have advantages in covertness with the multi-noise proof system. The nuclear technology in South Korea has seen the dramatic development since 1962 and in 1998 reached to the level that we have succeeded in the localization of nuclear plant and exported the world-class one-piece small-sized reactor (SMART) to UAE. To operate these reactors, we import the whole quantity of low-enriched uranium and having our own uranium enrich facility is not probable because of the budget and international regulations. With the ROK/US nuclear agreement revised on 2015 November, the enrichment of uranium that are available without special permission has changed up to 20%. According to the assumption that we use the 20% enrichment of Uranium on U.S. virginia class submarine, it is necessary to change the fuel after 11 years and it will cause additional cost of 1 billion dollars. But the replace period by the uranium's enrichment rate is not fixed so that it is possible to change according to the design of reactor. Therefore, I would like to make a suggestion on two types of design concepts of nuclear submarine that can be operated for 30 years without nuclear fuel change by using the 20% enriched uranium from ONNp.First of all, it is possible by increasing the size of reactor by 3 times and it results in the 1,000t increase of the weight. And secondly, it is by designing the one piece reactor to insert devices such as steam turbine, condenser into the inside of nuclear core like the Rubis class submarines of France.

• 대한화학회지
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• 제43권5호
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• pp.578-588
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• 1999

본 연구에서는 제 6차 교육과정에서 사용되고 있는 고등학교 화학I교과서의 내용이 그 교과서를 배우는 학생들에게 인지요구도 측면에서 적절한가를 알아보고, 학생들이 이해하기 어렵게 서술된 부분에 대해서 교과내용을 학생들의 인지수준에 맞게 재구성하는 학습전략을 제시하고자 하였다. 교과서 내용을 이해하는데 필요한 인지요구도를 알아보기 위하여 영국에서 개발된 교과내용 분류틀(CAT)을 사용하여 3종의 교과서 내용을 분석하였고, 학생들의 인지수준과 논리유형별 형성정도를 알아보기 위하여 논리적 사고력 검사지(GALT 축소본)를 사용하여 서울지역 고등학교 2학년 학생 821명을 대상으로 조사하였다. 학생들의 인지수준 조사결과는 학교별로 차이가 있었으나 평균적으로 형식적 조작 수준 46.3%, 과도기 43.0%, 구체적조작 수준 10.7%로 나타났다. 교과서의 인지요구도 수준 분석 결과는 출판사별로 대동소이하였으며, 대부분의 개념들이 초기 형식적 조작 수준으로 나타났다. 후기 형식적 조작 수준을 요구하는 개념으로는 `원자량과 분자량', '화학반응에서의 양적 관계', '원소의 주기적 성질' 등이었다. 이러한 연구 결과는 현장 교사들에게 어떤 개념들이 학생들에게 어려운가를 알 수 있게 해주고 학습전략을 구상하는데 많은 도움을 줄 수 있을 것으로 생각된다. 아울러 교과내용의 인지요구도를 낮추기 위해 본 연구의 결과를 이용하여 교과서의 내용을 재구성하는 과정을 제시하여 누구나 본 연구의 결과를 활용할 수 있도록 하였다.

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.277-300
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• 2016

Cold-formed steel (CFS) sections are becoming an increasingly popular solution for constructing floors in residential, healthcare and education buildings. Their reduced weight, however, makes them prone to excessive vibrations, increasing the need for accurate prediction of CFS floor modal properties. By combining experimental modal analysis of a full-scale CFS framed building and its floors and their numerical finite element (FE) modelling this paper demonstrates that the existing methods (based on the best engineering judgement) for predicting CFS floor modal properties are unreliable. They can yield over 40% difference between the predicted and measured natural frequencies for important modes of vibration. This is because the methods were adopted from other floor types (e.g., timber or standard steel-concrete composite floors) and do not take into account specific features of CFS floors. Using the adjusted and then updated FE model, featuring semi-rigid connections led to markedly improved results. The first four measured and calculated CFS floor natural frequencies matched exactly and all relevant modal assurance criterion (MAC) values were above 90%. The introduction of flexible supports and more realistic modelling of the floor boundary conditions, as well as non-structural $fa{\c{c}}ade$ walls, proved to be crucial in the development of the new more successful modelling strategy. The process used to develop 10 identified and experimentally verified FE modelling parameters is based on published information and parameter adjustment resulting from FE model updating. This can be utilised for future design of similar lightweight steel floors in prefabricated buildings when checking their vibration serviceability, likely to be their governing design criterion.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9543-9547
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• 2014

Background: The aim of this study was to investigate demographic features, dietary habits, and some possible risk factors for being susceptible to breast cancer in Iranian women. Materials and Methods: A study of dietary habits and breast cancer was conducted among 53 Iranian women with histological confirmed disease and 40 matched controls. A dietary habits questionnaire was used to evaluate the pattern of selected food intakes. The risk of cancer was analyzed after adjustment for confounding factors. Age, weight, body mass index (BMI), waist circumference, educational status, parity, lactation, marital status, menopause, history of estrogen therapy, and family history of breast disease or cancer were assessed among participants. Special attention was given to the relationship between consumption of high fat meat, milk, yogurt and cheese as well use of frying oils for frying foods, use of olive/liquid oils for cooking, removing fat from meat and poultry, removing chicken skin and not use of mayonnaise as salad dressing and the risk of breast cancer. Moreover, salad, vegetable and fruit consumption, and eating outdoors owere investigated. Results: Our results revealed significant lower education and higher BMI and waist circumference levels in patients with breast cancer. There was significantly increased breast cancer risk in overweight women in comparison with normal weight (OR=2.91, 95%CI 1.24 to 6.82). High intake of fat dairy products including milk and cheese was found to be a statistically significant factor for increasing breast cancer risk in models adjusting for age, BMI and education. Use of olive/liquid oils for cooking and avoidance of mayonnaise as salad dressing are related to lower risk of breast cancer. The frequency of vegetable and fruit consumption was significantly lower in patients with breast cancer compared to healthy women. Conclusions: Dietary habits might be risk factors for breast cancer among Iranian women. Adoption of a prudent diet could be an appropriate strategy for preventing breast cancer.